The present invention relates to rotor windings for electric machines. More particularly, the present invention concerns a method and apparatus for cooling superconductive materials used in windings for electric machines.
In the past, various types of cooling arrangements have been used for the windings of electric machines. In many applications involving conventional conductors, cooling is provided to remove unwanted heat.
Electrical superconductors are now available which exhibit very low resistance to the flow of electrical current. But, these superconductors must, in general, be maintained at cryogenic temperatures by the use of a cryogenic fluid. With superconductive excitation windings, proper cooling of the exciting winding is essential in order to obtain the superconductive properties of the winding material.
Some examples of both rotor and stator windings now in existence are illustrated in "Elektrische Maschinen" by Boedefeld/Sequenz, published by Springer-Verlag in 1971 at pages 347 et seq.
It should be apparent that the need continues to exist for a simple cooling scheme for superconductive windings which efficiently use a cryogenic cooling fluid.